So I've been running this for a few weeks and much like some other people, despite SLI being enabled I've actually taken a performance HIT on almost all gaming. Specifically BF3... Not too sure whats going on.

Now i will explain the problems and the fix for my motherboard(ASUS P5E64WS EVO):
The first problem was that i cannot activate the sli with both card on the blue pciexp (pciexp @16x 2.0) because the second blu pciexp wasn't working correctly.
So anatolymic told me to try first blue pciexp(pciexp @16x 2.0) and second black pciexp(pciexp @4x1.1). With this configuration i was able to enable sli on nv control panel but with sli enable the performances were the half.
This problem was caused from a bandwidth saturation, the thing was the same with both vga on the black pciexp.
So i retuned with both nvidia 9800GTX+ on the blue pciexp and after some work ANATOLYMIC found out that the driver recognized the vga on the second blue slot speed was less than pciexp 4x. In this way the drivers ''blocked'' the possibility to do the sli.
ANATOLYMIC build for me a special Hypersli (u can find here http://depositfiles.com/files/nknqag8xa ,only to unzip and click on hypersli and click install) and i was able to do the sli with both card on blue pciexp(@16x 2.0).
First i tried with the 190.62 and i had a 50% of increase of performance, after i tried with latest 290.53 and the increment was 63/64%!!!!!!
(NEW) With the 285.58 the increase of performance are little bit better than 290.53..around 65%.